在矩形
中,
点
分别在
上,且
.沿
将四边形
翻折至四边形
,点
平面
.
![](https://img.xkw.com/dksih/QBM/2021/7/8/2759900325306368/2777778682167296/STEM/055aee96639749ab9bfe87ca48f553d5.png?resizew=482)
(1)求证:
平面
;
(2)
四点是否共面?给出结论,并给予证明;
(3)在翻折的过程中,设二面角
的平面角为
,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/554f455de1180a8a6245b24ec9480a7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5c4cd264c97c1f261229925cc5a6761.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cf34605ceb15a969300a1121fc74f22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/946c16d99496d31ce4d87301a4793393.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c76e6c67644b8bad9bfe11c7ec3081d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7829855159327b2a87c3a424b3f7134a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a28d6477c85c5a4ac410a884e92fbe53.png)
![](https://img.xkw.com/dksih/QBM/2021/7/8/2759900325306368/2777778682167296/STEM/055aee96639749ab9bfe87ca48f553d5.png?resizew=482)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f235281692aa274a672d57fc400bd45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b12cffc313a181f666e3fc8e66b6f59.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45a8c036e6d2c152d0a16dbbe2bff905.png)
(3)在翻折的过程中,设二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1b43ff5a9a70210b4017c4c38b4258c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc24d605ad707ad0e76059d8a31f50d3.png)
更新时间:2021-08-02 23:48:06
|
相似题推荐
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在长方体
中,
分别是
和
的中点.
,
,
三线共点.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f66fb71b75b63594ebeeeebd1963eed5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
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解答题-证明题
|
适中
(0.65)
【推荐2】如图,在正方体
中,
为棱
的中点,点
在线段
上,且
.
,
,
表示
,
及
;
(2)求证:
,
,
,
四点共面.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a7bcc1efb8a2ff57d64b6d057da463.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c72a85bce8750a7675f2ae54979a3cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a754ad0537577221e7be168127d7cba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c085dbb9d78aef7d81c3f4d6855f067b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f7373300e952e2b90c7a66b682f5969.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b445e55dd4dd10b3fdeb0cb58e3bf8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7846d41a734339cbb28230afb2f98e1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95f4e5d98f1e6835fe1b074f10af0f21.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,在正三棱柱
(侧棱垂直于底面,且底面是正三角形)中,
,
,
,
分别是
,
,
的中点.
平面
;
(2)求证:
平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/147f76f731d718a2124dc0cf8eb99dc2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d8fe230436ad83b4bf41047d0333071.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf978f5b7d360c4978401204d18d158.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/770b4f16694b2bd79a1a93d776a82680.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4560fa4ad459b58b723c74bd24e51ebf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/877bda7e850ca4a33e517fcf4a082b42.png)
您最近一年使用:0次
【推荐2】如图,在三棱柱
中,
与
都为正三角形且
面
,
、
分别是
、
的中点.
![](https://img.xkw.com/dksih/QBM/2021/1/3/2628338649300992/2633913390252032/STEM/c3ae2601748644f5a98a3c061e651e2a.png?resizew=208)
求证:(1)平面
平面
;
(2)平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4310db23fc79936c7182361e652bab1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
![](https://img.xkw.com/dksih/QBM/2021/1/3/2628338649300992/2633913390252032/STEM/c3ae2601748644f5a98a3c061e651e2a.png?resizew=208)
求证:(1)平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f95f248c3c13e939e752c70fc6b397f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/161a4660d3a35f0de6af3d9068cf7bea.png)
(2)平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/497fcba48527feaff406cbddea38ceb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
【推荐1】如图1,在等腰梯形ABCD中,
,
,
,E为AD的中点.现分别沿BE,EC将△ABE 和△ECD折起,使得平面ABE⊥平面BCE,平面ECD⊥平面BCE,连接AD,如图2.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/6/ad507a81-977b-4d9f-a97e-49c8cd9a6f4a.png?resizew=292)
(1)若在平面BCE内存在点G,使得GD∥平面ABE,请问点G的轨迹是什么图形?并说明理由.
(2)求平面AED与平面BCE所成锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ccbff99696256fd402a2efb371862c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b35e692c54294045401f8add586eaaf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/645d46c17903078e0b38279353c5430d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/6/ad507a81-977b-4d9f-a97e-49c8cd9a6f4a.png?resizew=292)
(1)若在平面BCE内存在点G,使得GD∥平面ABE,请问点G的轨迹是什么图形?并说明理由.
(2)求平面AED与平面BCE所成锐二面角的余弦值.
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】如图,已知正方体
的棱长为
,
、
分别为棱
、
的中点.
平面
;
(2)设平面
与平面
的交线为
,求点
到直线
的距离及二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a8ec2583c364c079a7b1bfb1e8fe0c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2ad6b3d073d8dd1cb7d9c89116b9d81.png)
(2)设平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2ad6b3d073d8dd1cb7d9c89116b9d81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90fc2a8903fe0660f618e787c14be2cd.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,在四棱锥
中,底面
是边长为2的正方形,其它四个侧面都是腰长为
的等腰三角形.
![](https://img.xkw.com/dksih/QBM/2021/1/7/2630977995956224/2633630231011328/STEM/8b542fe7-f269-4431-ac9b-471401ac9860.png?resizew=258)
(1)求证:
;
(2)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://img.xkw.com/dksih/QBM/2021/1/7/2630977995956224/2633630231011328/STEM/8b542fe7-f269-4431-ac9b-471401ac9860.png?resizew=258)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccbd1316b9d1f0c1e71fd078deec61f6.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47d294d69caac577339f11f477b2047e.png)
您最近一年使用:0次
解答题-证明题
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适中
(0.65)
名校
【推荐2】如图,在多面体ABCDE中,
,
平面ABC,
,
,F为BC的中点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/e2184826-a943-4818-a2b6-e6646a64fe37.png?resizew=185)
(1)求证:
平面ADF;
(2)求二面角
的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9d7bd6df0e94731edb8f4649903de73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97f30533da2e1d2a958dc906c37eba9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e405b53cf66f14c54e9ae1e2a013f5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70abb2787196189aeb0e1c91018be094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab1a1fd2fc33e89f357cef772ff6cd0e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/e2184826-a943-4818-a2b6-e6646a64fe37.png?resizew=185)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a5f445af1ae136773cb338920552ff2.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0730e73ddbbf9184df15d3b1467e55e7.png)
您最近一年使用:0次